My dog got at my Sennheiser's and im wondering how i can replace the jack since thats where the decided to get at it...
ive replaced headphone jacks before but im not familiar with fiber cables and how they work...

Not sure what you mean by fiber cables, do you mean like a cloth covering or rubbery? If so, just cut it open to see what's inside. Some headphone cables are insulated with a type of lacquer coating, which you need to remove before soldering them to the new plug, normally I just burn it off with my solder gun after I've pulled back the cable sheath. The cables should be color coded, red right, green ground and last color left, but I still test them with my multimeter as some aren't even color coded logically.

so i used a wire cutter to strip down to the clean and fresh wires...
all i see is white fibre and a green, red, and gold... all three of these are twined between more fibre... im so confused...

If the white fiber is very fine and multi-stranded it is probably nylon strain relief thread. It's purpose is to add additional strength to the cable to take strain forces, like when you accidentally pull hard on the cable, off the conductors. You'll need to be careful to trim all of that fiber out of the way when soldering or you won't get a clean solder joint. You can do it manually with a magnifying glass, tweezers, and small scissors or blade. But you need to be careful to get it all. It's also possible to burn it away with a flame from a butane lighter, but that can also result in burning off the insulation on your conductors and leaving a carbon residue on them. In that case so you'd need to clean them carefully before soldering.

so i used a wire cutter to strip down to the clean and fresh wires...
all i see is white fibre and a green, red, and gold... all three of these are twined between more fibre... im so confused...

Red should be right, you should test the other two to identify left and the last wire would be ground (unless someone else here has repaired this specific pair and can tell you). You originally stated "that you had replaced headphone jacks" before, but if you don't know or are unsure you could always stop by a guitar (music equip store) shop and if they have service it's not that expensive, they know what to do. I would refrain from burning off the fiber as Pennhaven stated as it's only going to expose the individual color coded wires as well (causing short) and he's right the fiber is probably just nylon strain relief within the cable.